COMEDK 2024 Shift 1 Paper

In Young's double slit experiment, the position of the n‌th ‌ bright fringe is given by the equation:
xn=‌

nλD

d

where:
xn is the position of the fringe
n is the order number of the fringe
λ is the wavelength of the light used
D is the distance between the slits and the screen
d is the distance between the two slits
In this problem, we are given that the n‌th ‌ bright fringe for red light coincides with the (n+1)‌th ‌ bright fringe for violet light. This means:
nλ‌red ‌=(n+1)λ‌violet ‌
Given the wavelengths:
‌λ‌red ‌=6300∘A
‌λ‌violet ‌=4200∘A
We can substitute these values into the equation:

n⋅6300=(n+1)⋅4200
Simplifying this equation:
‌6300n=4200n+4200
‌2100n=4200
‌n=2
So, the value of ' n ' is 2 .
Thus, the correct option is:
Option A: 2